The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Labor is also ramping up its attack on the prime minister's paid parental leave scheme, calling the $5.5 billion an "unnecessary extravagance" and evidence of the government's "twisted priorities".

"This is a government that are looking to make cuts to areas that affect the most vulnerable in our community, whilst they look after the most wealthy," Labor frontbencher Anthony Albanese told reporters in Perth on Monday.

The government has rejected criticisms of the scheme as scaremongering and class politics.